In recent years, D2D communication in a traditional cellular network attracts widespread attention. In the D2D communication, a user equipment (UE) can communicate with another UE by means of a base station, and can also directly connect to and communicate with the another UE. The D2D communication can improve network performance: Spectrum utilization is improved, better coverage is implemented, and congestion is alleviated. Moreover, user experience can be improved due to a higher data rate, lower power consumption, and less serious congestion.
However, it is a challenge to obtain the foregoing benefits because interference exists between a cellular network and a D2D link. For example, if a downlink resource of a cellular network is used in the D2D communication (in a time division duplexing (TDD) system, it means that the D2D communication occurs in a downlink timeslot, and in a frequency division duplexing (FDD) system, it means that the D2D communication occurs in a downlink frequency), a downlink signal of a base station of the cellular network interferes with a receiving D2D UE, where the interference in this case is referred to as downlink interference in this specification. As shown in FIG. 1(a), a UE1, a UE2, and a UE3 are all within a coverage range of a base station BS1, and the UE2 and the UE3 are a D2D communication pair. The UE2 occupies a cell downlink channel during transmission from the UE2 to the UE3, and in this case, a downlink signal transmitted from the base station BS1 affects receiving, by the UE3, a signal transmitted by the UE2. For another example, if an uplink resource of a cellular network is used in the D2D communication (in a TDD system, it means that the D2D communication occurs in an uplink timeslot, and in an FDD system, it means that the D2D communication occurs in an uplink frequency), an uplink signal from another UE to a base station of the cellular network interferes with a receiving D2D UE, where the interference in this case is referred to as uplink interference in this specification. As shown in FIG. 1(b), a UE1, a UE2, and a UE3 are all within a coverage range of a base station BS1, and the UE2 and the UE3 are a D2D communication pair. The UE2 occupies a cell uplink channel during transmission from the UE2 to the UE3, and in this case, an uplink signal transmitted from the UE1 to the base station BS1 affects receiving, by the UE3, a signal transmitted by the UE2.